Re: Linux startup issue

[prj@po.cwru.edu (Paul Jarc)]

Jonathan de Boyne Pollard <J.deBoynePollard@Tesco.NET> wrote:
> 2.  "Restart" is better implemented as "svc -t" rather than as "svc
> -du", since the latter has the side-effect of changing the current
> state (to "up") whereas the former does not.

More specifically:
- If the service is down to begin with, "svc -t" will have no effect;
  "svc -du" will bring the service up, with automatic restarting.
- If the service is running once from "svc -o", then "svc -t" will
  take it down and leave it down; "svc -du" will take it down and
  bring it back up, with automatic restarting; "svc -do" will take it
  down and bring it back up, without automatic restarting, just as it
  was originally.  (supervise publishes enough information in
  supervise/status to distinguish the "-o" state from the "-u" state,
  but svstat doesn't report it.)
- "svc -d" sends SIGTERM and SIGCONT, so if the service is stopped
  with SIGSTOP, it will be allowed to run again so it can exit.
  "svc -t" sends only SIGTERM, which is not sufficient to kill a
  stopped process, but it can be combined with "svc -c" for the same
  effect as "svc -d" (without turning off restarting).


paul